text: // Copyright (c) 2009-2010 Satoshi Nakamoto
  // Copyright (c) 2009-2014 The Bitcoin developers
  // Copyright (c) 2016-2018 The PIVX developers
  // Copyright (c) 2018-2019 The BaaS developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #ifndef BITCOIN_TXMEMPOOL_H
  #define BITCOIN_TXMEMPOOL_H
  
  #include <list>
  
  #include "amount.h"
  #include "coins.h"
  #include "primitives/transaction.h"
  #include "sync.h"
  
  class CAutoFile;
  
  inline double AllowFreeThreshold()
  {
      return COIN * 1440 / 250;
  }
  
  inline bool AllowFree(double dPriority)
  {
      // Large (in bytes) low-priority (new, small-coin) transactions
      // need a fee.
      return dPriority > AllowFreeThreshold();
  }
  
  
  /** Fake height value used in CCoins to signify they are only in the memory pool (since 0.8) */
  static const unsigned int MEMPOOL_HEIGHT = 0x7FFFFFFF;
  
  /**
   * CTxMemPool stores these:
   */
  class CTxMemPoolEntry
  {
  private:
      CTransaction tx;
      CAmount nFee;         //! Cached to avoid expensive parent-transaction lookups
      size_t nTxSize;       //! ... and avoid recomputing tx size
      size_t nModSize;      //! ... and modified size for priority
      int64_t nTime;        //! Local time when entering the mempool
      double dPriority;     //! Priority when entering the mempool
      unsigned int nHeight; //! Chain height when entering the mempool
  
  public:
      CTxMemPoolEntry(const CTransaction& _tx, const CAmount& _nFee, int64_t _nTime, double _dPriority, unsigned int _nHeight);
      CTxMemPoolEntry();
      CTxMemPoolEntry(const CTxMemPoolEntry& other);
  
      const CTransaction& GetTx() const { return this->tx; }
      double GetPriority(unsigned int currentHeight) const;
      CAmount GetFee() const { return nFee; }
      size_t GetTxSize() const { return nTxSize; }
      int64_t GetTime() const { return nTime; }
      unsigned int GetHeight() const { return nHeight; }
  };
  
  class CMinerPolicyEstimator;
  
  /** An inpoint - a combination of a transaction and an index n into its vin */
  class CInPoint
  {
  public:
      const CTransaction* ptx;
      uint32_t n;
  
      CInPoint() { SetNull(); }
      CInPoint(const CTransaction* ptxIn, uint32_t nIn)
      {
          ptx = ptxIn;
          n = nIn;
      }
      void SetNull()
      {
          ptx = NULL;
          n = (uint32_t)-1;
      }
      bool IsNull() const { return (ptx == NULL && n == (uint32_t)-1); }
  };
  
  /**
   * CTxMemPool stores valid-according-to-the-current-best-chain
   * transactions that may be included in the next block.
   *
   * Transactions are added when they are seen on the network
   * (or created by the local node), but not all transactions seen
   * are added to the pool: if a new transaction double-spends
   * an input of a transaction in the pool, it is dropped,
   * as are non-standard transactions.
   */
  class CTxMemPool
  {
  private:
      bool fSanityCheck; //! Normally false, true if -checkmempool or -regtest
      unsigned int nTransactionsUpdated;
      CMinerPolicyEstimator* minerPolicyEstimator;
  
      CFeeRate minRelayFee; //! Passed to constructor to avoid dependency on main
      uint64_t totalTxSize; //! sum of all mempool tx' byte sizes
  
  public:
      mutable CCriticalSection cs;
      std::map<uint256, CTxMemPoolEntry> mapTx;
      std::map<COutPoint, CInPoint> mapNextTx;
      std::map<uint256, std::pair<double, CAmount> > mapDeltas;
  
      CTxMemPool(const CFeeRate& _minRelayFee);
      ~CTxMemPool();
  
      /**
       * If sanity-checking is turned on, check makes sure the pool is
       * consistent (does not contain two transactions that spend the same inputs,
       * all inputs are in the mapNextTx array). If sanity-checking is turned off,
       * check does nothing.
       */
      void check(const CCoinsViewCache* pcoins) const;
      void setSanityCheck(bool _fSanityCheck) { fSanityCheck = _fSanityCheck; }
  
      bool addUnchecked(const uint256& hash, const CTxMemPoolEntry& entry);
      void remove(const CTransaction& tx, std::list<CTransaction>& removed, bool fRecursive = false);
      void removeCoinbaseSpends(const CCoinsViewCache* pcoins, unsigned int nMemPoolHeight);
      void removeConflicts(const CTransaction& tx, std::list<CTransaction>& removed);
      void removeForBlock(const std::vector<CTransaction>& vtx, unsigned int nBlockHeight, std::list<CTransaction>& conflicts);
      void clear();
      void queryHashes(std::vector<uint256>& vtxid);
      void getTransactions(std::set<uint256>& setTxid);
      void pruneSpent(const uint256& hash, CCoins& coins);
      unsigned int GetTransactionsUpdated() const;
      void AddTransactionsUpdated(unsigned int n);
  
      /** Affect CreateNewBlock prioritisation of transactions */
      void PrioritiseTransaction(const uint256 hash, const std::string strHash, double dPriorityDelta, const CAmount& nFeeDelta);
      void ApplyDeltas(const uint256 hash, double& dPriorityDelta, CAmount& nFeeDelta);
      void ClearPrioritisation(const uint256 hash);
  
      unsigned long size()
      {
          LOCK(cs);
          return mapTx.size();
      }
      uint64_t GetTotalTxSize()
      {
          LOCK(cs);
          return totalTxSize;
      }
  
      bool exists(uint256 hash)
      {
          LOCK(cs);
          return (mapTx.count(hash) != 0);
      }
  
      bool lookup(uint256 hash, CTransaction& result) const;
  
      /** Estimate fee rate needed to get into the next nBlocks */
      CFeeRate estimateFee(int nBlocks) const;
  
      /** Estimate priority needed to get into the next nBlocks */
      double estimatePriority(int nBlocks) const;
  
      /** Write/Read estimates to disk */
      bool WriteFeeEstimates(CAutoFile& fileout) const;
      bool ReadFeeEstimates(CAutoFile& filein);
  };
  
  /** 
   * CCoinsView that brings transactions from a memorypool into view.
   * It does not check for spendings by memory pool transactions.
   */
  class CCoinsViewMemPool : public CCoinsViewBacked
  {
  protected:
      CTxMemPool& mempool;
  
  public:
      CCoinsViewMemPool(CCoinsView* baseIn, CTxMemPool& mempoolIn);
      bool GetCoins(const uint256& txid, CCoins& coins) const;
      bool HaveCoins(const uint256& txid) const;
  };
  
  #endif // BITCOIN_TXMEMPOOL_H
  